Tube for furnaces



Nov. 8, 1932. J, C, H0555 8 1,887,130

TUBE FOR FURNAC ES originai Filed oct. 2o, 192e s sheets-sheet 1 Il J J.C. HOBBS TUBE FOR FURNACES Original Filed Oct. 20, 1926 Nov. s, 1,932.

5 Sheets-Sheet 2 ,4 TTURNEYQ Nov. 8, 1932. J. c. HoBBs TUBE FOR FURNACES3 She'ets-Sheet 5 Original Filed Oct. 20, 1926 d ZZ /NVENTo/e W1Afro/NEM Patented Nov. 8, 1932 JAMES C. HOBBS, F PAINESVILLE, OHIO TUBE'FOR FUR-lucas Application led October 20, 1926, Serial No. 142,796.Renewed April 5, 1932.

This invention relates to tubes that Amay yhave liquid passing throughthem and be used as slag 'screen tubes in a furnace, or as furnace wallcooling tubes, andv will be understood from the description 1nconnection with the accompanying drawings, in Which- Fig. 1 is avertical section through a boiler furnace illustrating how the tubes maylbe installed; Fig. 2 is a section through one of the tubes and aportion of a header; Fig. 3 is an end view of the tube; Fig. 4 is asec'- tion, partly broken away, showing a. differ- .ent embodiment ofthe invention; Fig. 5 is a similar view taken at right-angles to Fig.

4, and Fig. 6 is an end view of thetube shown in Figs. LLand 5.

Heretofore, in attempting to use water tubes that are connected to theWater circulating system of a boiler as furnace Wall cooling tubes or aswater screen tubes, diiliculties.

have arisen because of the tubes burning, due to the fact that water isnot directed against those sides of the tubes exposed to the highesttemperatures. This difficulty is especially noticeable in horizontalwater screen tubes located near the bottom of the furnace, as thetendency of the steam to rise in such tubes prevents the water fromkeeping the upper side of the inside of such tubes wet. The inventionwill be particularly described in connection with water tube boilers butit is to be understood that it is useful in other places, such as oilstiils, for example, Where tubes are in danger ofv being burned outbecause the liquid flowing through the tubes is not kept in contactwhich the inside wall of the tube adjacent the places where intense heatstrikes the outside of the tubes.

In the accompanying drawings, reference 4.0 characters 10 and 11indicate the front and rear Walls, respectively, of a furnace that maybe provided with a fuel burner 12 near the top on the front sidethereof. A boiler, i the water tubes of which are shown at 13, may belocated above the furnace and receive heat therefrom. The side wallcooling tubes 14 of the furnace may. be connected to the watercirculating system of the boiler through headers 15 and 16 and pipes 17and 18 in the rwell-known manner. Pipe 17 may also be connected to the-header 19 from which water screen tubes 20 extend through the frontwall10 of the furnace across the lower-portion of the furnace, and throughthe rear wall 11 thereof, and are connected by elbows 21 to the `55 rearfurnace wall cooling tubes 22 which are, in turn, connected to a header23 and thence to the boiler.

In order to keep the inside of the tubes wet and thus prevent the samefrom being burned out, the tubes may be provided with means for causingthe water passing therethrough to partake of a rotary motion or tofollow a spiral path through the tubes. In the cinbodiment shown inFigs. 2 and 3, a spiral 65 strip 25 is shown for this purpose in one ofthe horizontal tubes 20. The end 26 of this strip is anchored in aflanged ring 27 that is inserted into the end of the tube 20 and keepsthe strip in place. This strip extends into the tube a short distancefrom the header 19 and serves to give the water a whirling motion as itpasses through the'tube 20,

thus causing the water to flow along the inside Wall of the tube in aspiral path and I5 keep the same wet. When this spiral strip is locatedin the cool end of the tube, as shown, very little, if any, steam willbe formed in the water before 'it passes beyond the end of the spiralstrip 25. The strip may, hogvever, extend any desired distance into tue.

In the form shown in Figs. 2 and 3 the spiral is cut away, as shown at28, at each turn along the upper side, so that steam can passlongitudinally through the tube without followingy the spiral path,while the water itself is caused to follow the spiral -path and keep theinside of the tube wet, even along its upper portion, or along the sidenext to the furnace. Under those conditions, the first action whichtakes place in the circulating system is a convection flow of water. If,as is sometimes the case, the starting is slow, there comes a time whenthe convection flow may stop altogether, due to the water throughout thesystem being at the same temperature. However this situation would notprevail for any greath length of time due to the application of heat tothe upper sides (ffl of the horizontally inclined tubes Which Wouldcause a certain amount of steam bubbles to be formed and as theseaccumulate in the top parts of the tubes and there is not sufiicient loWto carry them into the uptake part of the system, the tubes arein'danger oi beingburned out. The straight uninterrupted path istherefore provided through which the steam bubbles which may be trappedin the top of the tubes may more easily flow through the uptake part ofthe system and in this manner promote a rapid circulation through thesystem which is to be desired. When the rapid circulation is attainedthe deflection vanes in the tube cause the Water flowing therethrough toadopt a rotating path so that While the application of heat to the uppersurface of the tube Will tend to cause steam bubbles to accumulatethere, the rotating Water Will sweep such steam bubbles avvay andthereby obviate any danger of the tubes being burned out.`

In the embodiment shown in Figs. 4, y5 and 6, a rod 30 extends throughthe tube 20 and is held at both ends by means of the straps 3l thatextend across the tube, the rod 30 being threaded at both ends so thatnuts 32 may retain the same in place by being screwed up against thestraps 31. In this form deflector plates 33 are attached t0 the lowerside of the rod 30 as by spot-welding, as indicated at 34, thesedetlector plates being disposed at an angle to the aXis of the tube, sothat the Water Will be caused to partake of a circular or rotary motionto keep the purpose of aiding the distribution of the Water through thetubes from theheaders, since they interpose resistances which help toprevent any single tube from having too inuch Water pass therethrough.The spiral strips or defiector plates may be located not only in theslag screen tubes in the bottom of the furnace, but also in the Wallcooling tubes along the sides of the furnace. i

Various modifications and changes may be made Without departing fromthe' spirit or scope of this invention.

l claim:

l. ln a steam and water circulating system, a horizontally arranged tubehaving its upper portion exposed to a source of heat, and delec-.tingvanes in the tube constructed to cause the Water in the tube to rotate,said vanes being spaced from the Wall of the tube at said upper portion.

2. ln a steam and Water circulating system, a horizontally arranged tubehaving its upper portion exposed to a source of heat, anddeflectingvanes in the tube constructed to cause the Water in the tubeto rotate, said vanes having their upper portions removed and havingthere lower portions inclined to the direction of flow through the tube.

3. In a steam .and Water circulating system, a horizontally arrangedtube having its upper portion exposed to a source of heat, and means inthe tube to cause the Water to rotate therein during its passagetherethrough, said means leaving a space at the said upper portion ofthe tube.

y JAMES C. HOBBS.

